1. Field of the Invention
The present invention relates to an apparatus, such as a piezoelectric resonance device, having an electronic component located on a surface of a package member with a space provided between the electronic component and the package member.
2. Description of the Related Art
Some electronic devices require that a portion thereof does not contact a printed circuit board or substrate when mounted on the printed circuit board or substrate or the like. For instance, in a piezoelectric resonator, a resonating section thereof must be arranged such that a sufficient space between the resonating section and the printed circuit substrate is provided in order to prevent interference with the oscillation of the resonating section. In case of an exothermic electronic component, it is necessary to mount the electronic component such that a sufficient space between the printed circuit board or substrate and the component is provided in order to prevent heat from conducting to the printed circuit board or substrate and other nearby elements.
Various structures have been proposed for a piezoelectric resonator in order to create such a space.
FIG. 17 is a partially cutaway section view showing one example of a prior art structure for mounting a piezoelectric resonator.
As seen in FIG. 17, electrode lands 52a and 52b are located on a substrate 51. A piezoelectric resonator 53 is mounted in contact with the electrode lands 52a and 52b. The piezoelectric resonator 53 has a structure in which a terminal electrode 53b is located at one end of a piezoelectric plate 53a and a terminal electrode 53c is located at the other end. It is noted that a resonance electrode not shown is connected to the terminal electrodes 53b and 53c. 
The terminal electrodes 53b and 53c are connected to the electrode lands 52a and 52b via conductive adhesives 54a and 54b applied so as to have a certain thickness to prevent interference with the oscillation of a resonating section of the resonator 53.
That is, a gap 55 is created between the piezoelectric resonator 53 and an upper surface 51a of the substrate 51 by increasing a thickness of the conductive adhesives 54a and 54b. 
However, because the conductive adhesives 54a and 54b are liquid when they are applied, the conductive adhesive material is liable to flow along the upper surface 51a toward the center of the piezoelectric resonator 53 as shown by arrows A1 and A2 in FIG. 17. As a result, the resonating section is joined to the upper surface 51a of the substrate 51 via the conductive adhesive in the mounting structure, thereby degrading the resonating characteristics of the resonator 53. In addition, because the conductive adhesives 54a, 54b flow and extend along the upper surface 51a, the vertical dimension of the gap 55 is reduced and cannot be accurately or reliably provided.
Further, because the liquid conductive adhesives 54a and 54b are hardened after the application, the size and vertical dimension of the space 55 varies. Often, the resonating section of the resonator 53 contacts the upper surface 51a of the substrate 51, thereby damaging the resonating characteristics of the resonator 53.
In order to eliminate the aforementioned problems, there has been proposed a mounting structure in which spacers 56a and 56b are interposed between the terminal electrodes 53b and 53c and the electrode lands 52a and 52b as shown in FIG. 18. The spacers 56a and 56b are made of an electrically conductive material such as metal and are joined to the terminal electrodes 53b and 53c as well as the electrode lands 52a and 52b via conductive adhesive or solder. A space 55A is defined between the piezoelectric resonator 53 and the upper surface 51a of the substrate 51 by the vertical dimension of the spacers 56a and 56b. 
However, this structure requires preparation of spacers 56a and 56b having a very accurate size and shape and also requires a difficult and time-consuming process of applying the spacers 56a and 56b to mount the piezoelectric resonator 53.
Meanwhile, there has been disclosed a small package structure for storing a piezoelectric resonator and the like in Japanese Patent Laid-Open No. Hei. 5-83074. FIGS. 19a and 19b are a partially cutaway plan view and a section view, respectively, showing the package structure of this prior art device.
The electronic component 61 includes an insulating substrate 62 and a cap 63. A piezoelectric resonator 64 is stored within the package. Further, through hole electrodes 65a-65c are formed so as to extend through the substrate 62. The through hole electrodes 65a-65c are constructed by creating through holes extending through the substrate 62 and by applying an electrode material on the inner peripheral surfaces of the through holes. The inner peripheral surfaces of the through holes and the electrodes extend to the upper and lower surfaces so as to form flange-like portions.
The piezoelectric resonator 64 is joined to the through hole electrodes 65a-65c via conductive adhesives 66a-66c. The conductive adhesives 66a-66c are disposed in the through hole electrodes 65a-65c and are joined to the flange-like portion at the upper surface of the substrate 62 of the through hole electrodes 65a-65c. 
It is thought that the electronic component 61 allows an area outside of the cap 63 to be reduced so that the device can be miniaturized because the piezoelectric resonator 64 is led to the outside via the through hole electrodes 65a-65c. 
However, because the piezoelectric resonator 64 is joined to the through hole electrodes 65a-65c via the conductive adhesives 66a-66c in the electronic component 61, oscillation of the resonating section is damaged by the conductive adhesives 66a-66c which flow and spread during application thereof similar to the case of the mounting structure 51 shown in FIG. 17. In addition, similar to the prior art device shown in FIG. 17, the prior art device in FIG. 19(b) experiences a problem of not being able to reliably provide an accurate vertical dimension of the gap between the resonator 64 and the substrate 62, which problem is caused by the upper portions of the electrodes 65a-65c and the adhesives 66a-66c extending along and spreading out along the upper surface of the substrate 62.
As described above, there have been problems with degrading resonance characteristics caused by the mounting structure 51 shown in FIG. 17 and by the electronic component 61 shown in FIG. 19 because the space having a sufficient size or vertical dimension cannot be reliably provided due to the fluidity and spreading of the conductive adhesive.
Further, the mounting structure shown in FIG. 18 has had problems with the manufacturing and assembly process being complicated and costly because the spacers 56a and 56b have to be used.